The objectives of the project remains the study of the physiologic role of cartilage lysozyme. Our recent findings indicate that a certain pool of cartilage lysozyme is selectively associated with hyaluronic acid forming a complex of such a nature that it cannot be broken by dissociative solvents such as 4M guanidinium hydrochloride in cesium chloride density gradients. It is, therefore, postulated that lysozyme can occupy certain proteoglycan-binding sites on the hyaluronic acid molecule thereby regulating the size and/or degree of aggregation of the proteoglycan-aggregates. Furthermore, emphasis will be directed toward a detailed study of this hyaluronic acid-lysozyme complex by applying new isolation methods such as LaCl3 extraction and electrophoretic separation methods. This new LaCl3 extraction method yielded also a new proteolytic enzyme activity and low molecular weight proteins which act as trypsin or chymotrypsin or collagenase inhibitors. This aspect of the investigation will be pursued.